usb: musb: tusb6010: kill compile warning

Add an errno to failing case.

Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/musb/tusb6010.c b/drivers/usb/musb/tusb6010.c
index b73b036..ee8fca9 100644
--- a/drivers/usb/musb/tusb6010.c
+++ b/drivers/usb/musb/tusb6010.c
@@ -605,7 +605,7 @@
 
 	if (musb->board_mode != MUSB_OTG) {
 		ERR("Changing mode currently only supported in OTG mode\n");
-		return;
+		return -EINVAL;
 	}
 
 	otg_stat = musb_readl(tbase, TUSB_DEV_OTG_STAT);